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Unformatted text preview: CHAPTER 1 CHEMISTRY: MATTER AND MEASUREMENT PRACTICE PROBLEMS DR. ED TAVSS Units/unit conversions/dimensional analysis Classification of matter Significant Figures/Precision/Accuracy Miscellaneous 1 UNITS/UNIT CONVERSIONS/DIMENSIONAL ANALYSIS 12 The density of gold is 19.3 g/cm 3 . What is the density of gold in lb/in 3 ? A . 0.697 B. 19.3 C. 100 D. 1000 E. 1.20 10 3 454 g = 1 lb 2.54 cm = 1 in 19.3g/cm 3 lb/in 3 Convert numerator and denominator separately; then combine them. Numerator: 19.3g lb 19.3g x (1 lb/454g) = 0.0425 lb Denominator: cm 3 in 3 cm 3 x (1 in/2.54cm) 3 = 0.0610 in 3 Combining the numerator and denominator: 0.0425 lb/0.0610 in 3 = 0.697 lb/in 3 A 2 23 The value of gold is $472 per troy ounce. What is the value of the cube of gold 2.00 cm on a side? Given: 1 troy ounce = 31.1 g density of gold: 19.3 3 cm g A . $2340 B. $5460 C. $1520 D. $3410 E. $4250 The volume of a cube of gold = (2.00 cm) 3 = 8 cm 3 . Plan: Volume grams troy ounces $ 8 cm 3 x (19.3g/cm 3 ) x (1 troy ounce/31.1 g) x $472/troy ounce = $2343 21 Convert 251 min m into s m . A. 4.18 x 106 m/s B. 1.51 x 10 10 m/s C. 4.18 x 10 12 m/s D. 1.51 x 102 m/s E . 4.18 x 10 6 m/s Plan: m m; min sec 251 m/min x (1 m/106 m) x (1 min/60 sec) = 4.18 x 10 6 m/s 3 25 Diamonds have a density of 288 ct/in 3 . What is that density in g/cm 3 ? 1 carat = 0.200g, 1 in. = 2.54 cm (exactly) A. 0.285 g/cm 3 B. 22.6 g/cm 3 C. 17.6 g/cm 3 D. 0.146 g/cm 3 E . 3.51 g/cm 3 (288 ct/in 3 ) x (0.200g/ct) x ((1in) 3 )/((2.54cm) 3 ) = 3.51 g/cm 3 24 Which of the following is not a fundamental unit of SI? A. kg B . L C. mol D. m E. K kg, mol, m and K are all SI units. A dm 3 is called a liter, but neither dm nor L is an SI unit. 4 15 Pressure is force/area. The SI unit for force is kg m s2 . Express pressure in terms of base SI units. A . kg m1 s2 B. kg m 2 s2 C. kg m s2 D. kg m2 s2 E. kg m3 s2 Area would have units of m 2 . Pressure = (kg x m x s2 )/m 2 = kgs2 /m = kgm1 s2 11 Which prefix is correctly associated with its power of ten? A. m 106 B. M 10 3 C. 109 D . G 10 9 E. p 1015 m = milli = 103 M = mega = 10 6 = micro = 106 G = giga = 10 9 p = pico = 1012 5 2 Convert 55.6 F to kelvins. A. 13.1 K B . 286.3 K C. 315.7 K D. 341.3 K E. 68.1 K C o = (5/9)(F32) = (5/9)(55.632) = 13.11 K = 273 + C o = 273 + 13.11 = 286.11 11. The density of a diamond is 3.51 g/cm 3 and 1 carat = 0.200 g. The mass of a diamond whose volume is 2.8 mL is A. 4.0 carats B. 2.0 carats C . 49 carats D. choose this choice if none of the others is correct E. 170 carats 1 cm 3 = 1 mL Begin with what you know, and end with what youre trying to find....
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This document was uploaded on 11/02/2011 for the course GEN CHEM 162 at Rutgers.
 Spring '11
 tavss

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